Celestron Skymaster Binocular - 20x80 features high quality BAK-4 prisms and multi-coated optics for enhanced contrast. The Celestron Skymaster model has been designed and engineered to meet the special demands of extended astronomical or terrestrial viewing sessions. Carrying case included and integrated tripod adapter rod for ultra-stable tripod mounting. Each pair of Celestron Skymaster Binoculars feature high quality BAK-4 prisms and multi-coated optics for enhanced contrast, clear, sharp views and ultra sharp focus across the field of view. - 20x magnification porro prism binocular - Giant 80 mm objective lens offers maximum image brightness in low-light and long-range conditions - Ultra sharp focus across the field of view - Multi-Coated optics for sharp, clear views - Suitable for terrestrial or astronomical viewing - Protective rubber covering for ultra-firm grip - Large center focus knob for easy focusing - Integrated tripod adapter rod for ultra-stable tripod mounting - Long eye relief ideal for eyeglass wearers - Soft carrying case included for travel and safe storage - Limited Lifetime Warranty provides best protection and product support on the market Magnification: 20x Objective Lens Diameter: 80mm Focal Length of Objective Lens: 328.6mm (12.94") Angular Field of View: 3.7° Linear Field of View (@1000 yds) / @1000 m): 195 ft (65 m) Exit Pupil: 4mm Eye Relief: 18mm Close Focus: 108 ft Interpupillary Distance (max): 72mm Interpupillary Distance (min): 56mm Diopter Adjustment Range: -4 to +8 Twilight Factor: 40 Relative Brightness: 16 Limiting Stellar Magnitude: Ideal: 12.02 | Moderate: 11.02 | Poor: 10.02 Lens Coatings: Multi-Coated Prism Glass (Type): BaK-4 Prism Coatings: N/A Weight: 2126 g Environmental Protection: Water Resistant Nitrogen Filled: No Tripod Adaptable: Yes Carrying Case: Nylon Dimensions: 228mm x 120mm x 325mm Included Items: Objective lens caps | Rainguard | Carrying case | Neck strap | Lens cloth | Instruction manual